High-temperature fan



C. NYGREN HIGH- .Fune 21, 1949.

TEMPERATURE FAN 3 Sheets-Sheet 1 Filed April 24, 1947 June 21, 1949. c.NYGREN HIGH-TEMPERATURE FAN 3 Sheets-Sheet 2 Filed April 24, 1947 June21, 1949. V c, NYGREN 2,473,814

HIGH-TEMPERATURE FAN I Filed April 24, 1947 3 Shets-Sheet s PatentedJune 21, 1949 Carl: Nygremtluichigan City,-

Ind.,- assignor to Mich-iana Products/Corporation,. a corporationoflIndiana Application Airril 24, 1 94 3; Serial No. 7 43 515 41*Claims(Cl. 230-434) This: invention relates to centrifugal fansor:

blowers for handling gases anhigln temperatures,- and has foritsprincip'al object:- to' provide an improved, low cost assemblyofIsidemembers and blades that will. preserve dynamic'balance whileallowing free relativemoyement: of. the router:- portions in expandingand contracting.

Generally speaking, this is accomplished by fasteningthe-co'nverginginner portions of a plurality of blades to hub members of side pieces incircular serie'sl'a'n'dinterlocking the outer portions of. the bladeswith, shroudv portions of. the side pieces, allowing'freedo'm to move.Thus, the

- fixed relation of the blades andsid'e pieces is established andmaintained" by fastenings in a circle connecting the inner portions ofthe. blades with the hub portions of the SidBFpiBCBS and-leaving theparts otherwise free to expand andcon tract.

Specifically, this invention is an improvement over the constructiondisclosed in the Williams Patent No. 2,147,005, February 14, 1939.

Fig. 1 is a front elevation of a single inlet fan embodying theinvention, the upper portion being shown in vertical section;

Fig. 2 is a perspective view of one of the fan blades;

Fig. 3 is a side elevation of the fan shown in Fig. 1, a portion of oneof the side pieces being broken away and two of the blades beingremoved;

Fig. 4 is a perspective View of the plate for closing one side of thefan;

Fig. 5 is a perspective view of one of the pins by which the innerportions of the blades are made fast to the hub portions of the sidepieces;

Fig. 6 is a front elevation of a double inlet fan similar to that shownin Fig. 1, the upper portion being in section.

In the drawings, 10 indicates a hollow water cooled shaft upon which thefan portions are assembled and by which they are driven.

The fans include two side members generally indicated by A and B, eachhaving a hub portion- H, spokes l2, and a rim portion or shroud l3, hereshown as cast in one piece. The hub portions are secured in drivingrelation to the shaft by three keys l4 equally spaced about thecircumference.

In this particular embodiment, each shroud I 3 is provided with a seriesof radial grooves l5 spaced equldistantly to receive the correspondingedges l 6 of twelve blades H, which are slightly thickened and finishedalong the edges l 6 in order to fit closely within the grooves 15.

Each hub: portion H- has a circular flange I 8 finished: onits innerside [9 to cooperate with. th'efinishededges- Not the blades. Adjacentto those edges the blades are thickened at 2| and provided-with-pinholes 22 provided'with countersunk outer! portions-23, both of whichcorrespond to similar pin openings and counter-bored. por-- tions 2- and25' in the flanges l8. These openings and-counter-bores receive the pins26 having, large intermediate portions 21 by which the inner endportionsof the blades are made fast to the flanges l8 of thehub portions ll.

Thehub portion ll of the side piece B rests against a shoulder 28 on theshaft [Hand is held against that shoulder by a nut 29- threaded on theright end of the shaft Ill and locked by a l'ocknut- 3b and a lockwasher 3 I.

When the fan isassembledthe nut 292186917 up hard, and then backed offan amount corresponding to the expansion expected from the temperatureat which the fan is to give service. Then the lock washer 3| and thelock 30 are applied.

The double inlet fan shown in Fig. 6 corresponds almost exactly to thefan shown in Figs. 1, 2, and 3 except that the blades 32 are wider andthe shaft portion In between the side pieces is longer.

The side pieces are duplicates and may be used in both the single inletfan and the double inlet fan. In the former, it is necessary to providefor closure of one of the side pieces, and this may be done by machininga seat 34 on the inner side of the appropriate piece to receive thecircular plate or disc 35. Of course, such a disc can be made in onepiece with the side piece when that seems appropriate.

The fan shown in Fig. 3 of the Williams Patent No. 2,147,005 includesspacers 2c and 25, which must be machined all over, and in manyinstances the cost of that work will be approximately $240.00 for eachspacer. By eliminating those costly parts, changing the form of theinner portions of the blades, and providing for the fastening of thoseinner portions to the flanges IS on the hubs, a very much less costlyand more practical fan construction is obtained. The machine work onboth the hub portions and the blades is made very much simpler and lesscostly.

By changing the inner portions of the blades 29 of the Williams patentto the form shown in Figs. 1, 2, and 6, they are made much simpler toproduce and much more rugged and durable in the rigorous service at hightemperatures.

The construction here illustrated is for 24-inch the double fan being 12wide at the cirfans,

6%," wide cumference and the single fan being at the circumference.

I claim:

1. In a centrifugal fan, a shaft, side pieces spaced apart lengthwise onthe shaft and having hub portions and shrouds integrally connected byradiating spokes, a plurality of blades in circular arrangement aboutthe axis of the shaft with their outer portions diverging outwardly andthe side edges of their outer portions interlocked with the shrouds fornormal rotation but capable of freedom of expansion and contraction andwith their inner portions converging inwardly, and means in circularseries about the shaft making the inner portions of the blades fast tothe hub portions of the side pieces to hold the blades againstindividual bodily movement outwardly due to centrifugal force.

2. In a centrifugal fan, a shaft, side pieces spaced apart lengthwise onthe shaft and having hub portions and shrouds integrally connected byradiating spokes, a plurality of blades in circular arrangement aboutthe axis of the shaft with their outer portions diverging outwardly andthe side edges of their outer portions interlocked with the shrouds fornormal rotation but capable of freedom of expansion and contraction andwith their inner portions converging inwardly, and pins in circularseries about the shaft making the inner portions of the blades fast tothe hub portions of the side pieces to hold the blades againstindividual bodily movement outwardly due to centrifugal force.

3. In a centrifugal fan, a shaft, side pieces spaced apart lengthwise onthe shaft and having hub portions and shrouds integrally connected byradiating spokes, a plurality of blades in circular arrangement aboutthe aris of the shaft with their outer portions diverging outwardly andthe side edges of their outer portions interlocked with the shrouds fornormal rotation but capable of freedom of expansion and contraction andwith their inner portions converging inwardly and grasped between thehub portions, and means carried by at least one of the hub portions incircular series engaging said inner portions and holding the bladesagainst bodily movement outwardly due to centrifugal force.

4. In a centrifugal fan, a shaft, a pair of side pieces spaced apartlengthwise on the shaft, at least one of said side pieces having a hubportion and a shroud integrally connected by radiating spokes, therebyproviding inlet openings in the spaces between the spokes, a pluralityof blades in circular arrangement about the axis of the shaft with theirouter portions diverging outwardly and the edges at one side of eachouter portion interlocked with the shroud for normal rotation butcapable of freedom of expansion and contraction and with their innerportions converging inwardly, and means in circular series about theshaft making the inner portions of the blades fast to the hub portion ofthe named side piece to hold the blades against individual bodilymovement outwardly due to centrifugal force.

CARL NYGREN.

REFERENCES CITED The following references are of record in the f le ofthis patent:

UNITED STATES PATENTS Number Name Date 2,147,005 Williams Feb. 14, 19392,385,838 Nygren Oct. 2, 1945

